To develop a practical thyroid imaging reporting and data system (TIRADS) with which to categorize thyroid nodules and stratify their malignant risk. The institutional review board approved this retrospective study, and the requirement to obtain informed consent for the review of images and records was waived. From May to December 2008, ultrasonographically (US)-guided fine-needle aspiration biopsy (FNAB) was performed in 3674 focal thyroid nodules in 3414 consecutive patients. The study included the 1658 thyroid nodules (≥1 cm in maximum diameter at US) in 1638 patients (1373 women, 265 men) for which pathologic diagnosis or follow-up findings were available. Univariate and multivariate analyses with generalized estimating equations were performed to investigate the relationship between suspicious US features and thyroid cancer. A score for each significant factor was assigned and multiplied by the β coefficient obtained for each significant factor from multivariate logistic regression analysis. Scores for each significant factor were then added, resulting in an equation that fitted the probability of malignancy in thyroid nodules. The authors evaluated the fitted probability by using a regression equation; the risk of malignancy was determined according to the number of suspicious US features. The following US features showed a significant association with malignancy: solid component, hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape. As the number of suspicious US features increased, the fitted probability and risk of malignancy also increased. Positive predictive values according to the number of suspicious US features were significantly different (P < .001). Risk stratification of thyroid malignancy by using the number of suspicious US features allows for a practical and convenient TIRADS.

To retrospectively evaluate the diagnostic performance of power Doppler ultrasonography (US) in depicting vascularity and to determine whether the combination of vascularity and suspicious gray-scale US features is more useful in predicting thyroid malignancy than are gray-scale features alone. This was an institutional review board-approved retrospective study, with waiver of informed consent. A total of 1083 thyroid nodules in 1024 patients (median age, 51 years; range, 16-83 years), consisting of 886 women (median age, 50 years; range, 16-83 years) and 138 men (median age, 53 years; range, 19-74 years), were included. Nodules with marked hypoechogenicity, noncircumscribed margins, microcalcifications, and taller-than-wide shape were classified as suspicious according to gray-scale US criteria. Vascularity was classified as none, peripheral, and intranodular. The diagnostic performance of gray-scale and power Doppler US features was compared and classified as follows: criterion 1, any single suspicious gray-scale US feature; criterion 2, addition of any vascularity as one of the suspicious features to criterion 1; criterion 3, addition of peripheral vascularity to criterion 1; criterion 4, addition of intranodular vascularity to criterion 1; criterion 5, addition of no vascularity to criterion 1; criterion 6, American Association of Clinical Endocrinologists and Associazione Medici Endocrinology guidelines--all hypoechoic nodules with at least one of the following US features: irregular margins, intranodular vascular spots, taller-than-wide shape, or microcalcifications. Of 1083 nodules, 814 were benign and 269 were malignant. Intranodular vascularity was frequently seen in benign nodules and no vascularity was more frequent in malignant nodules (P < .0001, respectively). The area under the receiver operating characteristic curve (A(z)) of criterion 1 was superior (A(z) = 0.851) to that of criteria 2 (A(z) = 0.634), 3 (A(z) = 0.752), 4 (A(z) = 0.733), 5 (A(z) = 0.718), and 6 (A(z) = 0.806) (P < .0001). Vascularity itself or a combination of vascularity and gray-scale US features was not as useful as the use of suspicious gray-scale US features alone for predicting thyroid malignancy.

Background: Thyroid ultrasound (US) is used as the first diagnostic tool to assess the management of the disease. In spite of its importance, US is a very subjective method and highly dependent on the skill of the performer. There have been few reports evaluating thyroid US performance and even fewer reports of observer variability in US assessment. Therefore, we evaluated inter- and intraobserver variations in US assessment of thyroid nodules and diagnosis among four radiologists and estimated its diagnostic accuracy. Methods: A total of 204 thyroid nodules in 144 patients were reviewed. There were 89 benign and 115 malignant cases. Four radiologists with more than 5 years of experience independently reviewed US images twice at 6-week intervals. Echogenicity, composition, margin, shape, calcification, vascularity, and final assessment were evaluated. Inter- and intraobserver variations were determined with Cohen's kappa statistics, and accuracy was calculated. Results: For interobserver variations, echogenicity showed slight agreement (κ = 0.34); composition, margin, calcification, and final assessment had fair agreement (κ = 0.59, 0.42, 0.58, and 0.54, respectively); shape and vascularity showed substantial agreement (κ = 0.61 and 0.64, respectively). For intraobserver variability, almost all showed substantial agreement (κ > 0.61). Overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the four radiologists were 88.2%, 78.7%, 76.2%, 89.6%, and 82.8%, respectively. Conclusions: Experienced radiologists showed more than a moderate degree of agreement in US assessment of thyroid nodules, and their final assessments were highly accurate.

Shear-wave elastography (SWE) is a recently developed ultrasound technique that can visualize and measure tissue elasticity. In breast ultrasonography, SWE has been shown to be useful for differentiating benign breast lesions from malignant breast lesions, and it has been suggested that SWE enhances the diagnostic performance of ultrasonography, potentially improving the specificity of conventional ultrasonography using the Breast Imaging Reporting and Data System criteria. More recently, not only has SWE been proven useful for the diagnosis of breast cancer, but has also been shown to provide valuable information that can be used as a preoperative predictor of the prognosis or response to chemotherapy.

OBJECTIVE. The objective of our study was to investigate interobserver agreement for the diagnosis of malignant thyroid nodules using conventional B-mode ultrasound and real-time freehand ultrasound elastography.MATERIALS AND METHODS. Between December 2007 and February 2008, 45 patients (age range, 19–73 years; mean age ± SD, 45.0 ± 12.2 years) with 52 thyroid nodules were examined with conventional B-mode ultrasound and real-time freehand ultrasound elastography. All the patients were scheduled to undergo thyroid surgery because a thyroid nodule had been proven malignant on aspiration cytology. Three radiologists independently performed conventional ultrasound and elastography and analyzed the ultrasound images. Using conventional ultrasound, observers recorded the following information about nodular features: composition (solid, cystic, or mixed cystic–solid), echogenicity (hyperechoic, isoechoic, hypoechoic, or markedly hypoechoic), margin (well circumscribed, microlobulated, or irregular), calcificati...